KR100739424B1 - Exposure apparatus and method for manufacturing printed circuit board using inert gas injection - Google Patents

Abstract

A support for fixing the substrate to which the photosensitive agent is applied; A mask holder for disposing a mask having a predetermined pattern spaced apart from the photosensitive agent by a predetermined distance; A light source irradiating predetermined light onto the photosensitive agent using a predetermined pattern formed on the mask; And a housing having the support, the mask holder and the light source installed therein, and a housing having an injection hole through which an inert gas is injected to have a predetermined pressure, and a method of manufacturing a printed circuit board using the same. will be. By injecting an inert gas to block external air and irradiating ultraviolet rays in parallel without scattering, it is possible to reduce defects due to the adhesion from the vacuum exposure method in the contact exposure apparatus. In addition, whitening can be controlled and mask life can be extended by shielding external air in an inert atmosphere without PET when exposing solder resist.

Printed Circuit Boards, Exposure, Circuits, Solder Resist, Inert Gases

Description

Exposure apparatus and method for manufacturing printed circuit board using inert gas injection}

1 is a schematic configuration diagram of a contact exposure apparatus used in a circuit or solder resist exposure process according to the prior art;

2A to 2K are cross-sectional views showing the flow of a circuit pattern forming method of a general printed circuit board.

3 is a schematic structural diagram of an improved contact exposure apparatus according to a preferred embodiment of the present invention.

Figure 4 is a view showing the flow of a method of manufacturing a printed circuit board, in particular a circuit forming method according to an embodiment of the present invention.

5 is a schematic structural diagram of a projection exposure apparatus according to another preferred embodiment of the present invention.

6 is a schematic structural diagram of a direct imaging apparatus according to another preferred embodiment of the present invention.

7 is a flow chart of a solder resist coating method according to another preferred embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

300, 520, 625: Housing

105, 505, 635

110, 500, 600: Substrate

130, 535, 620: light source

305, 525, 630: inlet

120, 515: mask

610: Digital Micromirror Device

The present invention relates to a method of manufacturing an exposure apparatus and a printed circuit board, and more particularly, to an exposure apparatus and a method for manufacturing a printed circuit board for injecting an inert gas to expose the circuit and solder resist exposure.

As a technology to cope with high density of semiconductor chips and high signal transmission speed, a technology for directly mounting a semiconductor chip on a printed circuit board instead of CSP (Chip-Sized Package) or wire bonding is described. The demand is growing. In order to directly mount a semiconductor chip on a printed circuit board, it is necessary to develop a high density, high speed, small size, and high reliability printed circuit board capable of coping with high density of semiconductors.

The requirements for high density, high speed, small size, and high reliability printed circuit boards are closely related to the specifications of semiconductor chips, and many challenges such as miniaturization of circuits, high electrical characteristics, high speed signal transmission structure, high reliability, and high functionality There is. In response to these requirements, a printed circuit board technology capable of forming fine circuit patterns and micro via holes is required. As a result, circuit patterns formed on printed circuit boards are becoming increasingly densified and highly integrated.

Typically, a circuit pattern forming method of a printed circuit board includes a subtrative process, a full additive process, a semi-additive process, and the like. Among these methods, the semi-additive method is currently being applied as a microcircuit can be implemented.

The current state of the art can stably implement a circuit having a line / space of 18 to 20 μm using a photoresist having a thickness of 25 μm. However, in the next few years, line / space is expected to require fine circuit capability with 10-15µm. In addition, the circuit capability is directly related to the technical level of the photosensitive resist, and photosensitive resist makers are currently studying microcircuits, but have not made technical progress in the past 1-2 years. The reason why the technical development has not been made is that the technical level of the photoresist is not realized when the line / space is 15 µm or less, and the research will be weakened due to the lower PCB material cost. Therefore, it is a point in time that process improvement and self-improvement of an exposure apparatus are required as a method for enhancing a fine circuit resolution.

Currently, exposure techniques are mainly used to form fine circuits for high integrated circuits or fine line widths for high density recording. Such exposure technology is a technique of forming a circuit by irradiating light such as ultraviolet rays to a dry film including a laminated photosensitive resist, forming a predetermined pattern by applying a developer, and then etching an metal layer by applying an etchant again. Commonly used to form patterns.

In addition, the above-described exposure technique is a solder resist coating used to prevent the adhesion of lead to the unnecessary portion so that it can be buried only in the portion where the solder used when mounting (mounting) the component on the substrate Also used for.

1 is a schematic configuration diagram of a contact exposure apparatus used in a circuit or solder resist exposure process according to the prior art.

Referring to FIG. 1, a substrate 110 is placed on a support 105 of the contact exposure apparatus 100. The photosensitive agent 115 is coated on the surface of the substrate 110. The mask 120 having a predetermined pattern printed thereon is brought into close contact with the photosensitive agent 115. Then, the ultraviolet (UV: Ultraviolet) from the light source 130 is irradiated through the lens 125.

The light source 130 uses scattered light or parallel light, and in order to block air between the mask 120 and the dry film 115 by using a vacuum apparatus (not shown), vacuum contact is performed to strongly compress the mask 120. do.

Due to this, there is a concern that the mask 120 may be damaged relatively, and due to a defect of foreign matter generated in the mask 120, a large number of defective products may be produced when the printed circuit board is mass-produced later using the same mask 120. There is a possibility.

In addition, in the solder resist exposure process in addition to the circuit exposure process, in order to prevent whitening phenomenon, as described above, a vacuum apparatus is used to close the outside air to block external air, and the dry film 115 on the mask 120 and the substrate 110 is used. To improve the adhesion between the liver. Alternatively, PET (Polyester) is attached to the package product line to block outside air and prevent whitening.

Partial defects may occur due to the adhesion by vacuum, and there is a problem that the manufacturing cost increases due to the use of expensive PET. Therefore, the existing build-up packaging substrate method can not meet the emerging market needs due to the structural limitations of the method of manufacturing a printed circuit board.

Accordingly, in order to solve the above problems, the present invention provides a vacuum contact method in the contact exposure apparatus by injecting an inert gas during exposure for generating a circuit pattern to block external air and irradiate the UV or scattered light in parallel without being scattered. The present invention provides a method of manufacturing an exposure apparatus and a printed circuit board using an inert gas that can overcome the foreign matter defect due to adhesion and reduce the shortening of the life due to the mask damage.

In addition, the present invention provides a method of manufacturing an exposure apparatus printed circuit board using an inert gas that can reduce the process cost and manufacturing cost due to the use of expensive PET during the solder resist exposure.

In addition, the present invention provides a great benefit in the contact type exposure apparatus during solder resist exposure, and extends the life of the mask and overcomes the phenomenon that the solder resist ink smears of the exposure apparatus and printed circuit board It provides a manufacturing method.

In addition, the present invention provides a method of manufacturing an exposure apparatus printed circuit board using an inert gas to increase the exposure resolution by injecting an inert gas to block the outside air to prevent whitening phenomenon in the solder resist exposure to be sufficient exposure. do.

Other objects of the present invention will be readily understood through the following description.

In order to achieve the above objects, according to an aspect of the present invention, a support for fixing a substrate coated with a photosensitive agent; A mask holder for disposing a mask having a predetermined pattern spaced upward from the photosensitive agent by a predetermined distance; A light source for irradiating predetermined light onto the mask; And a housing having the support, the mask holder and the light source installed therein, and a housing having an injection hole into which an inert gas is formed to form an inert gas atmosphere therein. .

Preferably, the injection hole is connected to the mask holder, it is possible to create a space under the mask holder in an inert gas atmosphere.

In addition, the predetermined interval between the mask and the photosensitive agent may be 1 ~ 5000㎛.

In order to achieve the above objects, according to another aspect of the invention, the support for fixing the substrate to which the photosensitive agent is applied; A light source for irradiating predetermined light; A pattern forming unit for allowing the predetermined light to have a predetermined pattern in two dimensions; A projection lens frame penetrating the light having the predetermined pattern and projecting the light on the photosensitive agent; And a housing having the support, the light source, the pattern forming unit, and the projection lens frame therein and having an injection hole into which an inert gas is formed to form an inside of the inert gas atmosphere. An apparatus may be provided.

Preferably, the pattern forming unit may be a mask holder for disposing a mask on which the predetermined pattern is formed between the light source and the projection lens frame. Alternatively, the pattern forming unit may be a digital micromirror device having a plurality of micromirrors and individually controlling the micromirrors so that the predetermined light has the predetermined pattern.

In addition, the injection hole may be connected to the projection lens frame to form a space below the projection lens frame in an inert gas atmosphere.

The projection lens frame may allow the predetermined pattern to be reduced, enlarged, or projected onto the photoresist with the same size.

Here, the predetermined light irradiated by the light source may have a wavelength of 150 nm to 800 nm, and the inert gas may be a periodic table group 0 element gas or nitrogen (N ₂ ) gas. In addition, the photosensitive agent may be a dry film or a solder resist.

In order to achieve the above objects, according to another aspect of the present invention, in the method of manufacturing a printed circuit board by exposure by a printed circuit board exposure apparatus in which an inert gas is injected to form an inert gas atmosphere in the housing, (a Providing a substrate coated with a photosensitive agent in the printed circuit board exposure apparatus; (b) disposing the mask at a predetermined interval on the photosensitive agent; (c) irradiating predetermined light onto the photosensitive agent using a predetermined pattern formed on the mask; And (d) may be provided a method of manufacturing a printed circuit board comprising the step of developing the photosensitive agent.

Preferably, the inert gas atmosphere in the printed circuit board exposure apparatus may be formed in the lower space including the mask. Here, the predetermined interval between the mask and the photosensitive agent may be 1 ~ 5000㎛.

In order to achieve the above objects, according to another aspect of the present invention, in the method of manufacturing a printed circuit board by exposure by a printed circuit board exposure apparatus in which an inert gas is injected to form an inert gas atmosphere in the housing, (a Providing a substrate coated with a photosensitive agent in the printed circuit board exposure apparatus; (b) irradiating light having a predetermined pattern formed two-dimensionally on the projection lens frame; (c) projecting the predetermined light onto the photosensitive agent; And (d) may be provided a method for manufacturing a printed circuit board comprising the step of developing the photosensitive agent.

Preferably, the step (b) comprises (b-1) disposing a mask on which the predetermined pattern is formed between a light source and the projection lens frame, wherein light is irradiated onto the mask from the light source. Can be. Or the printed circuit board exposure apparatus includes a digital micromirror apparatus having a plurality of micromirrors, wherein step (b) controls each micromirror individually so that the predetermined light has the predetermined pattern. can do.

In addition, an inert gas atmosphere in the printed circuit board exposure apparatus may be formed in a space below the projection lens frame. The projection lens frame may allow the predetermined pattern to be reduced, enlarged, or projected onto the photoresist with the same size.

Preferably, the photosensitive agent is a dry film, the substrate is a copper foil layer is formed, (e) may further comprise the step of forming a predetermined circuit pattern by etching the copper foil layer.

Alternatively, the photoresist is a solder resist, the substrate is a circuit pattern is formed, and may further comprise the step (e) heat drying and surface treatment of the solder resist.

Preferably, the predetermined light irradiated by the light source has a wavelength of 150 nm to 800 nm, and the inert gas may be a periodic table group 0 element gas or nitrogen (N ₂ ) gas.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, before describing the preferred embodiments of the present invention in detail, a general method for manufacturing a printed circuit board will be described. Here, the description will focus on the cross-sectional manufacturing method of the multilayer substrate, but the present invention is not limited to the cross-sectional manufacturing method of the multilayer substrate. In addition, the printed circuit board described herein includes all substrates for electrical signal transmission between electronic components. For example, the printed circuit board according to the present invention includes a rigid substrate, a flex substrate, a single-sided / multi-faceted / multilayer substrate, a semiconductor mounting substrate (BGA, FBGA, TBGA), and the like. In describing the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Numbers (eg, first, second, etc.) used in the description of the present specification are merely identification symbols for sequentially distinguishing identical or similar entities.

2A to 2K are cross-sectional views showing a flow of a circuit pattern forming method of a general printed circuit board. The circuit pattern forming method of a printed circuit board is shown using a semiadditive process.

Referring to FIG. 2A, an internal circuit pattern is formed outside the core layer. Here, the inner layer raw material meeting the product specifications is cut and a predetermined internal circuit pattern is formed using a dry film and a working film. Here, the inner layer may be scrubbed, the inner layer printed film applied, and the inner layer exposure / development process may be performed. Then, a process of performing adhesion strengthening treatment (Brown (Black) Oxide) is performed before the inner layer on which the circuit pattern is formed is adhered to the outer layer. In other words, the surface of the copper foil is oxidized using a chemical method to enhance the roughness of the surface of the copper foil, thereby performing a surface treatment to improve adhesion in the lamination. Thereafter, insulating layers 212 and 212 ′ are stacked on both surfaces or one surface of the inner layer substrate 211.

Referring to FIG. 2B, the insulating layer 212 is processed by mechanical drilling or laser to form a via hole a for circuit connection between layers.

Referring to FIG. 2C, an electroless copper plating layer 213 is formed on the insulating layer 212 and the via hole a region in order to electrically connect the layers and form a circuit pattern on the surface of the insulating layer 212.

Referring to FIG. 2D, the dry film 220 is coated on the electroless copper plating layer 213. The dry film 220 includes a photosensitive layer 221 and a Mylar layer 222.

Referring to FIG. 2E, the mask 230 in which a predetermined pattern is printed is brought into close contact with the myra layer 222 of the dry film 220 and then irradiated with ultraviolet rays. The mask 230 may be a working film or a glass mask.

At this time, the unprinted portion 231 of the mask 230 transmits ultraviolet rays to form a cured portion 221a on the photosensitive layer 221, and the black portion 232 on which a predetermined pattern is printed is exposed to ultraviolet rays. The non-hardened portion 221b is formed in the photosensitive layer 221 because it does not penetrate.

Referring to FIG. 2F, the mask 230 is separated from the mira layer 222.

Referring to FIG. 2G, the myra layer 222 is peeled off and removed from the dry film 220.

Referring to FIG. 2H, by performing the developing process, the uncured portion 221b of the photosensitive layer 221 is removed by the developer, and only the hardened portion 221a of the photosensitive layer 221 remains to form a plating resist. Form a pattern.

Referring to FIG. 2I, an electrolytic copper plating layer 214 is formed on a circuit pattern, a via hole a region, or the like, in which a plating resist pattern is not formed.

Referring to FIG. 2J, the cured portion 221a of the photosensitive layer 221 is peeled off and removed.

Referring to FIG. 2K, the electroless copper plating layer 213 and the electrolytic copper plating layer 214 are sprayed with an etchant to remove the electroless copper plating layer 213 except for the circuit pattern and the via hole a region.

The above process involves exposure to form a circuit pattern, and the process for solder resist coating is also similar to FIGS. 2A to 2E. Instead of the dry film 220, a solder resist ink is used, and the mask 230 has a pattern for solder resist coating instead of a circuit pattern.

In FIG. 2A, a pretreatment process such as forming roughness on the copper foil surface such that the solder resist ink is in close contact with the substrate, such as brush polishing, is performed on the substrate on which the circuit pattern is already formed. Then, the solder resist is applied, the solder resist exposure process is performed using an adaptively designed solder resist exposure film in the previous step, and the solder resist ink is cured through UV cure and thermal cure. . The development process of removing the solder resist ink is performed, and various post-processes including surface treatment and electrical / final inspection are performed.

3 is a schematic configuration diagram of an exposure apparatus of an improved contact type according to an exemplary embodiment of the present invention. Referring to FIG. 3, the improved contact type exposure apparatus includes a support 105, a mask holder 310, a light source 130, and a housing 300.

The support 105 allows the substrate 110 to be exposed to be fixed at a predetermined position. In general, before the exposure process is performed, the photosensitive agent 115 (in this example, a dry film) is applied in advance as the substrate 110 undergoes a pretreatment process, a photosensitive agent coating process, and a soft bake process. Here, the board | substrate 110 is a disk or core layer in which the copper foil layer was formed in one surface or both surfaces.

The dry film as the photosensitive agent 115 is composed of a cover layer, a photosensitive layer, and a mylar layer. The cover layer is peeled off when the dry film is laminated and serves to protect the photosensitive layer, and is formed of polyethylene. The photosensitive layer is formed of a binder polymer and polymerized by reacting with predetermined light. The Myra layer serves to protect the photosensitive layer until development, and also inhibits the reaction with oxygen by preventing the external environment, that is, blocking the oxygen. In addition, the polyester (Polyester) material has important characteristics in transmittance and static electricity.

In addition, the photosensitive agent 115 may be a solder resist (SR). In this case, the substrate 110 to be exposed is a substrate on which a circuit pattern is formed using the dry film described above. A user applies a solder resist on the substrate 110 on which a desired circuit pattern is formed, and makes it possible to bury only a solder necessary for mounting parts on the substrate 110 through an exposure process.

The mask holder 310 supports the mask 120 on which a pattern to be patterned is formed on a substrate. The mask 120 is spaced apart from the photosensitive agent 115 applied on the substrate 110 by a predetermined interval and disposed to be parallel to the substrate 110. The mask may be a glass mask (GM) capable of forming a fine circuit pattern.

The distance between the mask 120 and the photosensitive agent 115 may be 1 to 5000 μm to increase the resolution while preventing diffraction of light due to the space between the mask 120 and the photosensitive agent 115. In particular, the effect is great when the light emitted from the light source 130 is scattered light.

The light source 130 allows light to be irradiated in parallel to the mask 120 vertically. Accordingly, the light source 130 is composed of a lamp, a high-efficiency elliptical reflector, an infrared filter, a switch, a mirror, and the like, and a collimation lens 125 may be attached to emit light in parallel.

Light irradiated from the light source 130 is light having a wavelength of approximately 150 to 800 nm. For example, use a mercury (Hg) -xenon (Xe) lamp that emits light at g-line (436 nm), h-line (405 nm), or i-line (365 nm) wavelengths, or UV light at a wavelength of 248 nm. A KrF-Fn excimer laser that emits light, an ArF-F excimer laser that emits ultraviolet light of 193 nm wavelength, and a fluorine F2 laser that emits UV light of 157 nm wavelength can be used.

The housing 300 is provided with a support 105, a mask holder 310, and a light source 130. In addition, in the present invention, an inlet 305 for injecting an inert gas from the outside of the housing 300 is provided to create an inert gas atmosphere inside the housing 300. In addition, the housing 300 is purged with air (especially oxygen) existing inside due to the inert gas injection, it may be further provided with a discharge port (not shown) for taking it out. In addition, the housing 300 may further include a vacuum pump (not shown) for injecting inert gas and discharging internal air.

The injection hole 305 of the housing 300 may be connected to the mask holder 310 (305a). Although the entire interior of the housing 300 may be formed in an inert gas atmosphere, the portion where the high precision parallel light is actually required is between the mask 120 and the photosensitive agent 115 spaced by a predetermined interval. Accordingly, the inert gas injected through the injection hole 305 connected to the mask holder 310 is sprayed onto the mask 120 so that a relatively high pressure inert gas atmosphere is formed between the mask 120 and the photosensitive agent 115. do. Alternatively, the mask frame may be formed between the mask 120 and the photosensitive agent 115, and then an inert gas may be injected only into the internal space to form an inert gas atmosphere. In this case, the inert gas has a specific gravity, and has a characteristic of being accumulated from a downward direction.

Injection of the inert gas may be performed only during the exposure time by the light source 130. Continued composition of the inert gas atmosphere within the housing 300 or between the mask 120 and the photoresist 115 may result in costly use of the inert gas, which may temporarily create an inert gas atmosphere only at the moment of exposure. Can be.

Herein, the inert gas usually refers to six elements of helium (He), neon (Ne), (Ar), (Kr), (Xe), and radon (Rn) belonging to group 0, and relatively other substances. Nitrogen (N) or the like that is difficult to react may be included. The inert gas serves to cause the light irradiated from the light source to proceed in parallel without being scattered or diffracted. The resolution of the pattern patterned on the photosensitive agent 115 is increased by preventing scattering of light by air existing in the housing 300, in particular, between the mask 120 and the photosensitive agent 115.

In addition, the inert gas has an advantage to prevent the effects caused by the air to purge the air (purge). That is, since the air is purged using an inert gas, there is no need to closely contact the mask 120 and the photosensitive agent 115, as shown in FIG. And foreign matter defects can be prevented.

4 is a flow chart illustrating a method of manufacturing a printed circuit board, in particular a circuit forming method, using the improved contact type exposure apparatus shown in FIG. 3.

Referring to FIG. 4, in step S400, an original plate having a copper foil surface laminated on both surfaces or one surface thereof, that is, a core layer is provided.

In step S405, the dry film 150 is applied to the original plate laminated copper foil. The dry film peels off the cover layer and applies a photosensitive layer and a myra layer.

In step S410, the disc 110 to which the dry film 150 is applied is fixed to the support 105 in the housing 300 of the improved contact exposure apparatus shown in FIG. 3. The mask 120 having the pattern desired by the user is formed using the mask holder 310 to be spaced apart from the disc 110 on the support 105 by a predetermined interval.

In operation S415, an inert gas is injected into the housing 300 to form an inert gas atmosphere. In this case, the inert gas may be injected into the entire housing 300 to form the entire interior of the housing 300 in an inert gas atmosphere, or injected into the mask holder 310 to inert only between the mask 120 and the dry film 115. A gas atmosphere can also be created.

In operation S420, the mask 120 is irradiated with predetermined light while the inert gas atmosphere is formed inside the housing 300. The predetermined light may be light having a wavelength of 150 to 800 nm.

In step S425, after the exposure process is completed, a developer is applied to form a predetermined pattern, and then an etchant is used to etch the metal layer to form a circuit. In the case of a semi additive method, a circuit is formed by copper plating over the space of the dry film 150 formed after development.

5 to 6 illustrate a noncontact type exposure apparatus according to another exemplary embodiment of the present invention. The non-contact type exposure apparatus includes a projection exposure apparatus or a direct imaging (DI) device.

First, FIG. 5 is a schematic configuration diagram of a projection exposure apparatus. Referring to FIG. 5, the projection exposure apparatus includes a support 505, a light source 535, a projection lens frame 510, a mask holder 530, and a housing 520.

The support 505 allows the substrate 500 to be exposed to be fixed at a predetermined position. In general, before the exposure process is performed, the photoresist (dry film or solder resist ink) is applied to the substrate 500 according to a pretreatment process, a photoresist coating process, and a soft bake process. Here, when the photosensitive agent is a dry film, the board | substrate 500 is a disk or core layer in which the copper foil layer was formed in one surface or both surfaces. Alternatively, when the photoresist is a solder resist, the substrate 500 is a substrate having a circuit pattern desired by a user. The circuit pattern may be formed on one or both surfaces of the substrate, and the substrate may be a single layer or a multilayer substrate.

The mask holder 530 supports the mask 515 in which a pattern to be patterned on the substrate 500 is formed in a black portion. The mask 515 is positioned between the projection lens frame 510 and the light source 535, so that the beam irradiated from the light source 535 passes through to form the projection beam in the projection lens frame 510.

Here, the mask 515 may be a glass mask GM or a film mask. In the case of a film mask, a function of a mask is performed by adhering a film on which a predetermined pattern is formed using a double-sided adhesive tape on glass.

The light source 535 allows light to be irradiated in parallel to the mask 515 vertically.

The light irradiated from the light source 535 is light having a wavelength of approximately 150 to 800 nm. For example, use a mercury (Hg) -xenon (Xe) lamp that emits light at g-line (436 nm), h-line (405 nm), or i-line (365 nm) wavelengths, or UV light at a wavelength of 248 nm. A KrF-Fn excimer laser that emits light, an ArF-F excimer laser that emits ultraviolet light of 193 nm wavelength, and a fluorine F2 laser that emits UV light of 157 nm wavelength can be used.

Projection lens frame 510 includes one or more lenses. The projection beam passing through the mask 515 passes through one or more lenses in the projection lens frame 510 to be projected onto the photoresist applied on the substrate 500. In FIG. 5, the pattern of the mask 515 is projected onto the photoresist applied on the substrate 500 in a 1: 1 size, but the projection of the mask pattern may be reduced or enlarged in size.

The housing 520 is provided with a support 505, a mask holder 530, a light source 535, and a projection lens frame 510 therein.

In addition, in the present invention, an inlet 525 for injecting inert gas from the outside of the housing 520 is provided to create an inert gas atmosphere inside the housing 520. In addition, the housing 520 is purged with air (especially, oxygen) existing inside due to the inert gas injection, and may be further provided with a discharge port (not shown) for pulling it out. In addition, the housing 520 may further include a vacuum pump (not shown) for injecting inert gas and discharging internal air.

In addition, the injection hole 525 of the housing 520 may be connected to the projection lens frame 510 by the injection hole extension 525a. Although the entire interior of the housing 520 may be formed in an inert gas atmosphere, a portion where a high precision parallel light is actually required is a space A through which the projection beam passes to reach the substrate 500. Therefore, the inert gas injected from the outside through the injection hole extension 525a connected to the projection lens frame 510 is sprayed downward to form the space below the projection lens frame 510 in the inert gas atmosphere. In this case, the inert gas has a specific gravity, and has a characteristic of being accumulated from a downward direction.

In addition, the injection hole 525 of the housing 520 may be sprayed on the upper portion of the substrate 500 by another injection hole extension 525b.

In the case where the photoresist is a solder resist ink, the solder resist ink causes whitening when in contact with air. As a result, many product defects occur. In the past, if solder resist was used, PET had to be used to prevent contact between air and solder resist ink. However, since the inert gas dust is formed on the substrate using the inert gas described above, the contact between the solder resist ink and the air is blocked, thereby preventing the occurrence of whitening without expensive PET.

Herein, the inert gas usually refers to six elements of helium (He), neon (Ne), (Ar), (Kr), (Xe), and radon (Rn) belonging to group 0, and relatively other substances. Nitrogen (N) or the like that is difficult to react may be included. The inert gas serves to cause the light irradiated from the light source to proceed in parallel without being scattered or diffracted. Inert gas also serves to block contact of the photosensitizer with air.

In addition, the inert gas atmosphere only needs to be formed during the exposure time.

The projection exposure apparatus is capable of exposing with a step function, and has an excellent degree of alignment and can form a fine pattern uniformly. It is applied to a micro circuit of a printed circuit board (PCB), a chip on flexible printed circuit (COF), a reel to reel (R2R), and the like.

A method of manufacturing a printed circuit board by exposure by a projection exposure apparatus in which an inert gas is injected to form an inert gas atmosphere in a housing is as follows.

In a first step, a substrate having a photosensitive agent applied thereto is provided in a projection exposure apparatus. In a second step, a mask on which a predetermined pattern is formed is disposed on the projection lens frame. In a third step, a predetermined light is irradiated onto the mask using a light source and projected onto the photosensitive agent through the projection lens frame. In the fourth step, the photosensitive agent is developed to form a circuit pattern.

FIG. 6 shows a direct imaging device, which is another non-contact type exposure apparatus. Referring to FIG. 6, the direct imaging apparatus includes a support 635, a light source 620, a projection lens frame 605, a digital micromirror device 610, and a housing 625.

Similar to the projection exposure apparatus shown in FIG. 5, except that there is no mask on which a predetermined pattern is formed. Instead of a mask, there is a digital micromirror device 610.

The digital micromirror device 610 is a reflective display device including a plurality of (eg, hundreds of thousands of) micromirrors (ie, aluminum thin mirrors). Each micromirror can be controlled individually. There is no need for a large-sized mask, and flexibility for a variety of models is good. There is no mask maintenance cost, it is used in a large area exposure method, and the exposure quality of the pattern is excellent. It is applied to partition walls, electrode patterns, printed circuit boards, and the like.

Each micromirror of the digital micromirror device 610 is individually controlled so that a pattern desired by a user is patterned on a photoresist on the substrate 600 fixed on the support 635.

The light source 620 may be a laser diode, and irradiates a beam to the digital micromirror device 610 through the illumination optical system 615. In the digital micromirror device 610, the beam is patterned to have a predetermined pattern, is projected onto the projection lens frame 605 to form a projection beam, and the projection beam is irradiated to the photoresist on the substrate 600.

The method of creating an inert gas atmosphere is similar to the projection exposure apparatus shown in FIG. The entire interior of the housing 625 is formed in an inert gas atmosphere, or only a portion under the projection lens frame 605 is formed in an inert gas atmosphere, or the lower portion only from a height such that the photoresist on the substrate 600 is blocked from contact with air. Inert gas atmosphere can be formed. In addition, the inert gas atmosphere only needs to be formed during the exposure time.

The projected beam with a predetermined amount of light causes the photoresist to react with the monomer to form a polymer to form a pattern image.

A method of forming a circuit by exposure by a direct imaging device in which an inert gas is injected to form an inert gas atmosphere in a housing is as follows.

In a first step, there is provided a substrate coated with a photosensitive agent in the direct imaging device. In a second step, a digital micromirror device is formed in which a plurality of micromirrors are individually controlled on a projection lens frame to form a predetermined pattern. Irradiate light. In the third step, the light irradiated onto the digital micromirror device projects the pattern generated by the micromirror through the projection lens frame onto the photosensitive agent. In the fourth step, the photosensitive agent is developed to form a circuit pattern.

In the above, the method of forming an inner layer circuit or an outer layer circuit in a printed circuit board and the exposure apparatuses used for exposure have been described.

Hereinafter, a description will be given of a method of using each of the exposure apparatuses illustrated in FIGS. 3, 5, and 6 for exposure during a solder resist coating process in a manufacturing process of a printed circuit board.

7 is a flowchart of a solder resist coating method according to another preferred embodiment of the present invention.

Referring to FIG. 7, in step S700, a substrate on which a circuit pattern is formed is provided. The circuit pattern may be formed on one side or both sides of the substrate, and may be a single layer or a multilayer substrate.

Here, before the solder resist ink is applied, pretreatment may be performed to remove the foreign matter and copper oxide (Cu) oxide film and the oil retaining component from the substrate and to increase adhesion to the solder resist ink.

In step S705, the substrate subjected to the pretreatment process is completely covered with solder resist ink. Application methods include screen coating methods, roll coating methods, curtain coating methods, spray coating methods, and the like.

Immediately after application of the solder resist ink, the solder resist ink is wet and therefore vulnerable to foreign matter, thus undergoing a preliminary drying process. The predrying process preserves the flat surface state immediately after coating and facilitates the exposure operation in the post-exposure exposure process.

In step S710, the mask on which the pattern image is formed is disposed at a predetermined position. In the case of the contact exposure apparatus shown in FIG. 3, the substrate 110 is arranged to be spaced apart from the substrate 110 by a predetermined interval (preferably, about 1 to 5 μm). In the case of the projection exposure apparatus illustrated in FIG. 5, the light source 535 is disposed. And a mask are disposed between the projection lens frame 510. In the case of the direct imaging device illustrated in FIG. 6, the pattern is formed by arranging the digital micromirror device 610, which is a device for forming a predetermined pattern instead of a mask.

In operation S715, an inert gas is injected into the housings 300, 520, and 625 constituting the exposure apparatus to form an inert gas atmosphere. The entire housing 300, 520, 625 is formed in an inert gas atmosphere. Alternatively, in the case of the contact exposure apparatus shown in FIG. 3, the inlet 305 of the inert gas is connected to the mask holder 310 to form an inert gas atmosphere between the mask 120 and the solder resist ink. In the case of the projection exposure apparatus illustrated in FIG. 5 and the direct imaging apparatus illustrated in FIG. 6, injection holes 525 and 630 of inert gas are connected to the projection lens frames 510 and 605 so that the projection lens frames 510 and 605 or less are provided. The space is created in an inert gas atmosphere.

PET must be used when the contact exposure apparatus is used to prevent whitening due to air during solder resist ink exposure, or when the projection exposure apparatus or the direct imaging apparatus, which is a non-contact exposure apparatus, is used. However, according to the present invention, due to the inert gas atmosphere composition, it is possible to block direct air contact with the solder resist ink, thereby preventing the whitening phenomenon and eliminating the need for using expensive PET.

In step S720, a predetermined light, that is, ultraviolet rays having a wavelength of 150 ~ 800nm is irradiated so that the photosensitive agent reacts with the polymer according to the pattern formed on the mask to form and cure the polymer.

In step S725, the solder resist ink portion not exposed to ultraviolet rays in the previous step is removed using a developer (for example, Na ₂ CO ₃ + H ₂ O).

In step S730, the unreacted photoinitiator and monomer are reacted with a polymer using ultraviolet rays in the exposure process, and the final heat drying is performed to complete curing.

In step S735, surface treatment is performed so that solder can be attached.

As described above, the manufacturing method of the exposure apparatus and the printed circuit board according to the present invention in the contact exposure apparatus by injecting an inert gas during the exposure to generate a circuit pattern to block the outside air and irradiated in parallel without ultraviolet light scattering It is possible to overcome the foreign matter defect caused by the adhesion and reduce the shortening of the life due to the mask damage. This can be more effective in the scattered light.

In addition, the process cost and manufacturing cost can be lowered by not using expensive PET during the solder resist exposure.

In addition, it is possible to greatly benefit from a contact type exposure apparatus during solder resist exposure, prolong the mask life and overcome the phenomenon that the solder resist ink bleeds out.

In addition, by injecting an inert gas to block the outside air to increase the exposure resolution and prevent the whitening phenomenon in the solder resist exposure can be sufficient exposure.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (23)

delete delete A support for fixing the substrate to which the photosensitive agent is applied; A mask holder for disposing a mask having a predetermined pattern spaced upward from the photosensitive agent by a predetermined distance; A light source for irradiating predetermined light onto the mask; And And a housing having an injection hole into which the support, the mask holder and the light source are installed, and which inert gas is injected into the inert gas atmosphere. The predetermined interval between the mask and the photosensitive agent is 1 to 5000㎛ printed circuit board exposure apparatus. delete delete delete delete delete delete delete delete delete delete In the method of manufacturing a printed circuit board by exposure by a printed circuit board exposure apparatus in which an inert gas is injected to form an inert gas atmosphere in the housing, (a) providing a substrate coated with a photosensitive agent in the printed circuit board exposure apparatus; (b) disposing the mask at a predetermined interval on the photosensitive agent; (c) irradiating predetermined light onto the photosensitive agent using a predetermined pattern formed on the mask; And (d) developing the photosensitizer, The predetermined distance between the mask and the photosensitive agent is a manufacturing method of a printed circuit board, characterized in that 1 ~ 5000㎛. delete delete delete delete delete delete delete delete delete

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